Frank w



(Model.)

F. W. MIX.

LOCK.

No. 404,048. Patented May 28, 1889.

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FRANK IV. MIX, OF NEV BRITAIN, CONNECTICUT.

L O C K SPECIFICATION forming part of Letters Patent No. 404,048, datedMay 28, 1889.

Application filed March 3l, 1888. Serial No. 269,072. (Model.)

To all whom, it may concern:

Be it known that I, FRANK WV. MIX, a resident of New Britain, in thecounty of Hartford and State of Connecticut, have invented certain newand useful Improvements in Locks for Post-Office Lock-Boxes; and I do Yhereby declare the following to be a full, clear,

and exact description of the invention, such as will` enable othersskilled in the art to which it appertains to make and use the same.

My invention relates to an improvement in tumbler-locks of a classspecially adapted for the securing in closed adjustment of doors onboxes or pigeon-hole receptacles which are arranged in tiers for thesafe delivery of mail-matter in post-oiiices or other similar uses. Inorder to render locks for this particular use secure and permit analteration to be effected in its locking mechanism when a key is lost orin the hands of unauthorized parties, a lock has been devised andpatented which will allow such a change to be made. In the use of such alock it is necessary that the works which operate to secure theslidebolt shall require a positive action of the key to open it or lockVit.

It has been found in use that Where safetylocks of the type aboveindicated are applied to the lock-boxes of post-offices the require mentof a positive action of the key to lock the door is to a certain extentinconvenient, as parties in the hurry of business frequently withdrawthe key after unlocking the door of the box and deposit the same intheir pocket-s. If the door of a lock-box having a safety-lock made asabove stated is inadvertently closed by slamming it when the bolt is inlocked position, the slide-bolt will be bent or the shock may break theglass front plate of the box; or, if the key is Withdrawn while thelock-bolt is retracted, the door will of course be left unlocked.

The object of my present invention is to Aprovide a means to obviate theinconvenience of having to use the key of a positive-action tumbler-lockwhich is applied to the door of a lock-box postfofiice delivery, ashereinbefore mentioned, and also avoid the disadvantages which lmightresult from the closure of a door the lock of which has been left in alocked position Aof its bolt. I

With these objects in view my invention consists in certain features ofconstruction and combination of parts, which will be hereinafterdescribed, and pointed out in the claims.

Referring to the drawings, Figure l is a plan view of a lock-casing withits cap-plate removed, as are all the interior works with the except-ionof the slide-bolt plate and an attached bolt. Fig. 2 is a side elevationin section of the lock-casing with the slide-bolt in place. Fig. 3 is adetached enlarged View of the slide-bolt plate, the latching outer endof an attached slide-bolt being shown in section.

A represents the casing of a lock, preferably cut and stamped into form.This casing is rectangular, with an integral back plate, B, the rim orwall a being bent therefrom and joined at the corners to form a casingwith a smooth interior surface. The back plate, B, is perforated atseveral points for the accommodation of studs and other mechanicaldetails of the lock mechanism not necessary to show in thisconnection,it being specified that the Working parts of the lock are ofsuch a form as to secure the slide-bolt in either a locked or unlockedposition until moved by a proper key.

Vithin the casing A the slide-bolt plate C is placed so as to rest uponthe back plate, B, the general form of the Slide-bolt platecorresponding with that of the casing, and it is of such comparativewidth that it Will slide neatly therein, the plate B being long enoughto allow the necessary throw of the saine in either direction to lock orunlock a door on which the lock is affixed.

The slide-bolt plate C is adapted to afford support to tumblermechanism'that is employed to control the throw of this bolt-plate, asbefore stated, which may be varied in form and method of operation;hence it is not shown.

Upon the side edge of the slide-bolt plate B-a proper distance to aifordthe requisite strength-the slide-bolt D is integrally formed by bendinga portion of the material of the plate B at a right angle thereto, thebolt thus produced having sufiicient length to permit it to extendthrough a slot formed near the corner l) of the casing-wall a.

The length of the slide-bolt D is made to IOO suit the relative positionof the lock upon a lock-box door to which it is attached, as the 'widthand formation of the door may arbitrarily control the placing of thelock and consequent length required for the bolt to engage its keeperproperly. The form of the door is not material, and as letter lock-boxesare a well-known device it is not deemed necessary to show one in thisconnection.

The outer end of the slide-bolt D, at a point outside the casing, isslotted edgewise a proper depth to afford two parallel walls, c, betweenwhich the latch-plate E islocated. This plate is triangular in form andpivoted to the ears cl, which are formed on the walls c at their topcorners.

It may here be specified that the space fi, formed between the twoparallel walls c on the end'of the bolt D, may be produced by a propertool that is adapted to remove a portion of the material from the solidend of the bolt. A preferred form for the construction of this end ofthe bolt B is shown in Fig; l, which consists in the attachment to theside of the bolt proper of an offset jaw, e, which is riveted orotherwise secured thereto, so as to produce a space for the receptionbetween the two pieces of the latch-plate E.

The upper end of the latch-plate is rounded to conform to the shape ofthe ears d, and a shoulder, f, is produced on the' outer edge of theplate E, at the heel of the rounded upper end of this plate, whichshoulder is slotted to allow one end of the finger-spring F to beembedded in the latch-plate E, the free end of this springengaging theterminal wall of the slotv or space t', so as to force outwardly thelatch-plate and hold it normally so projected.

lis

When the outer edge of the latch-plate E is outwardly projected, as juststated, said edge will be given such an inclination from a perpendicularline as to form a yielding latch, the edge being slightly curved tofacilitate its yielding action when it is caused to abut against theedge of the door-frame. From the point 7L the lower portion of thelatch-plate E is rounded to form an arc of a circle, the center of whichis the axis of the pivot-support of this plate, so that the vibration ofthe latch-plate on its pivot will cau se its free curved lower edge tohave sliding` contact with the check bar or step 7a, against which'aprojecting toe, m, formed on the in-l ment of the latch-plate by thespring.

It is evident from the foregoing. description of the spring attachment,as applied to slidebolts of locks which are moved positively and heldagainst retraction unless a proper i against the edge of the door-frameand yield readily and sufficiently to permit said door to be entirelyclosed and locked without the use of the key.

The construction of the spring-latch E Will prevent any tampering withthe spring-latch or opening of the door without the proper key, as thecoaction of the check-bar k and toe m will convert the latch-plate intoa firm abutment, which will not yield to 'an outward pull of the dooruntil the slide-bolt is withdrawn in a legitimate manner.

Slight changes might be made in the 'constructive details of thislatching device without departing from the spirit of my. inv en tion 5hence I do not wish to restrict myself to the exact forms herein shown;but, Y

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent, isj l. In a lock, the combination, with avslid'- in'g bolt, of a latch pivote'd to and projecting beyond theouter end of the bolt andwholly supported thereby, substantially as s'etforth.

2; In a lock, the combination, with a sliding bolt having an open slotformed in its outer end, of' a yielding latch pivoted within said slotand located wholly outside the lockcasing, substantially as set forth.

3. In a lock, the combination, with a sliding bolt havinga stop formedthereon, of a latch pivoted to and carried by the sliding bolt andarranged to project beyond its outerY end, said latchbeing-provided witha projection that engages a stop on the bolt for limiting its outwardmovement, and a spring for forcing the latch to the limit of its outwardmovement, substantially as set forth.

In testimony whereof I have signed this speciiication in the presence oftwo subscribing witnesses.

FRANK MIX.

Vitne'sses:

A. N. ABBE, E. L. PRIOR.

IOO

